Freeman is the author of the book where the F169 number comes from. Normally only collectors with the book quote Freeman numbers so I assumed you had one! Wherever the info was about it being one of only 10 is not correct. The info about the N's I don't think applies when trying to tell the difference between F169 and the F168. The only differences are the reverses, common is type D and the F169 has type E. The differences are pretty small though (even on as new coins). The waves are more finely cut (impossible to tell after wear), as you know the 1 is right above a tooth and the exergue (the space containing the date) is slightly smaller, which is also impossible to tell when the edge has started melting into the coin.